1. Field of the Invention
The present invention relates to a printed circuit board of a portable device such as portable telephone, PHS, or PDA and a structure of a casing in which the printed circuit board is mounted and, more particularly, to a deformation-resistant mounting structure of a portable device.
2. Description of the Prior Art
Since a portable device such as a portable telephone or PDA becomes lighter, thinner, and smaller, the user can easily carry it in his/her pocket or the like.
FIG. 1 is an exploded perspective view showing a general schematic structure of a conventional technique of this kind.
In FIG. 1, a plurality of screws 105 are inserted in through holes 204 of a printed circuit board 203 and screwed into prepared holes 102 of bosses 106 of a casing 101, thereby sandwiching the printed circuit board 203 of a portable device between the top surfaces of the bosses 106 and the screws 105 and mounting the printed circuit board 203 on the casing 101.
Due to light weight, thinness, and small size, the user sometimes forgets that he/she carries a portable device. Consequently, an electric failure is increasingly caused by a drop of the portable device from a breast pocket when the user stoops down or by pressure applied on the portable device in a pocket of pants when the user sits down.
By a mechanical stress such as drop or pressure, distortion occurs in a soldered portion between the printed circuit board of the portable device and an electric part mounted on the board.
Because of the distortion, disconnection occurs due to a crack in the soldered portion, and it causes an electric failure.
For solving the problem, in Japanese Unexamined Utility Model No. 63-115251 as a first conventional technique, a printed circuit board in which at least one slit or groove is formed so as to surround a portion sandwiched by holding members has been proposed.
Techniques similar to the first conventional technique are disclosed in Japanese Patent Application Laid-Open Nos. 64-18300, 9-181403, and 11-330640 as second, third, and fourth conventional techniques, respectively.
The first to fourth conventional techniques, however, have the following drawbacks.
Specifically, deformation in a printed circuit board cannot be prevented only by a plurality of slits or grooves formed around portions for fixing the printed circuit board to a casing, the mechanical stress of an external force cannot be sufficiently absorbed, and an effective area of the printed circuit board is reduced by the area of the portions in which the slits or grooves are formed.
In order to overcome the aforementioned disadvantages, the present invention has been made and accordingly, has an object to provide a novel deformation-resistant mounting structure of a portable device, capable of reducing an electric failure by decreasing the distortion, that is, capable of improving the mechanical strength of a portable device.
Another object of the present invention is to provide a novel portable information terminal device enabling convenience and reliability of a portable information terminal or the like to be improved.
According to a first aspect of the present invention, there is provided a deformation-resistant mounting structure of a portable device comprising: a printed circuit board in which a plurality of though holes are formed; a casing having a plurality of bosses each having a seat and a prepared hole or a threaded hole, the seat is provided for mounting the printed circuit board, a plurality of screws each being inserted into the prepared hole or the threaded hole of each of the plurality of bosses through each of the plurality of through holes, wherein each of the plurality of through holes is formed in a slit shape, and wherein when the casing is deformed, each of the plurality of screws displaces along a direction of the slit shape.
According to a second aspect of the present invention, there is provided a deformation-resistant mounting structure of a portable device comprising: a printed circuit board in which a plurality of though holes are formed; a chassis having a plurality of bosses each having a seat and a prepared hole or a threaded hole, the seat is provided for mounting the printed circuit board, a plurality of screws each being inserted into the prepared hole or the threaded hole of each of the plurality of bosses through each of the plurality of through holes, wherein each of the plurality of through holes is formed in a slit shape, and wherein when the chassis is deformed, each of the plurality of screws displaces along a direction of the slit shape.
According to a third aspect of the present invention, there is provided a deformation-resistant mounting structure of a portable device comprising: a printed circuit board in which a plurality of though holes are formed; a casing having a plurality of bosses each having a seat and a male screw, the seat is provided for mounting the printed circuit board, a plurality of screw nuts, into each of which each of the male screws is inserted through each of the plurality of through holes, wherein each of the plurality of through holes is formed in a slit shape, and wherein when the casing is deformed, each of the plurality of male screws displaces along a direction of the slit shape.
According to a fourth aspect of the present invention, there is provided a deformation-resistant mounting structure of a portable device comprising: a printed circuit board in which a plurality of though holes are formed; a chassis having a plurality of bosses each having a seat and a male screw, the seat is provided for mounting the printed circuit board, a plurality of screw nuts, into each of which each of the male screws is inserted through each of the plurality of through holes, wherein each of the plurality of through holes is formed in a slit shape, and wherein when the chassis is deformed, each of the plurality of male screws displaces along a direction of the slit shape.
According to a fifth aspect of the present invention, there is provided a deformation-resistant mounting structure of a portable device comprising: a printed circuit board in which a plurality of though holes are formed; a casing having a plurality of bosses each having a seat and a pillar on the seat, the seat is provided for mounting the printed circuit board, the pillar having a prepared hole or a threaded hole, the pillar being inserted into each of the through holes, a plurality of screws each being inserted into the prepared hole or the threaded hole of each of the pillars, wherein each of the plurality of through holes is formed in a slit shape, and wherein when the casing is deformed, each of the plurality of pillars displaces along a direction of the slit shape.
According to a sixth aspect of the present invention, there is provided a deformation-resistant mounting structure of a portable device comprising: a printed circuit board in which a plurality of though holes are formed; a chassis having a plurality of bosses each having a seat and a pillar on the seat, the seat is provided for mounting the printed circuit board, the pillar having a prepared hole or a threaded hole, the pillar being inserted into each of the through holes, a plurality of screws each being inserted into the prepared hole or the threaded hole of each of the pillars, wherein each of the plurality of through holes is formed in a slit shape, and wherein when the chassis is deformed, each of the plurality of pillars displaces along a direction of the slit shape.
According to a seventh aspect of the present invention, there is provided a deformation-resistant mounting structure of a portable device comprising: a printed circuit board in which a plurality of though holes are formed; a casing having a plurality of bosses each having a seat and a pillar on the seat, the seat is provided for mounting the printed circuit board, the pillar having a male screw, the pillar being inserted into each of the through holes, a plurality of screw nuts, into each of which each of the male screw is inserted, wherein each of the plurality of through holes is formed in a slit shape, and wherein when the casing is deformed, each of the plurality of pillars displaces along a direction of the slit shape.
According to a eighth aspect of the present invention, there is provided a deformation-resistant mounting structure of a portable device comprising: a printed circuit board in which a plurality of though holes are formed; a chassis having a plurality of bosses each having a seat and a pillar on the seat, the seat is provided for mounting the printed circuit board, the pillar having a male screw, the pillar being inserted into each of the through holes, a plurality of screw nuts, into each of which each of the male screw is inserted, wherein each of the plurality of through holes is formed in a slit shape, and wherein when the chassis is deformed, each of the plurality of pillars displaces along a direction of the slit shape.